Rotary fluid unit



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ROTARY FLUID UNIT Filed Ilarch 29. 1927 4 Sheets-Sheet 4 Snom/1to1Patented Jan. 7, 1930 UNITED STATES PATENT OFFICE BEGINALD J. S. PIGOTT,0F NEW YORK, N. Y.

ROTARY FLUID UNIT Application led March 29, 1927. Serial No. 179,236.

My invent-ion relates to devices for delivextremely flexible drive andis widely suitering fluids and more particularly to rotai'y able for thepropulsion of motor vehicles and units of a type capable of delivering avariaother motor vehicles and other transportation ble volume of fluidper unit of time at conmeans as well as in industrial uses. Among 5stant speed or conversely, of maintaining a other advantages of suchtransmissions, be- I5 constant volume at variable speed. sides theconstant-speed-variable-volume fealn the present forms of rotaryunitsture are that one unit may supply several gear, inipeller orotherwise-the volume of motors in parallel-such as might be a stokerfluid delivered is a function of the speed and feed-where, shouldfinemotor be stalled by 10 only by varying the speed can the volume be partof the mechanism which it drives, the 60 varied. This has been alimiting factor in remaining motors will speed up to take care suchunits and has prevented their use where of the output of the unit andkeep the mechotlierwise it would be greatly extended, not anisin to itscapacity although one part has only for transferring fluids from onepoint to failed. Likewise, motors may be placed in another but as ameans to supply and control Series to drive separate but dependentmechaa fluid motor. nisms in syiiclironism at any given speed. As

In general, my invention embraces a pluthe whole unit output must passthrough each rality of revolving members enclosed in a motor, thestoppage of one will cause all of casingdriven from a source of power-asthe others to stop and so prevent damage or is well known in the art.The amount of loss. 70 fluid delivered is then dependent upon the ef-The form which I have chosen to illustrate fective width of the faces ofthe revolving my invention is that ofagear pump although members. Aslong as the width of these it will be understood that other forms of r0-faces remains constant, the volume of fluid tary units having a,plurality of rotors can 5 delivered will also remain constant for anfyequally well be adapted to the same principles given speed. llowever, bychangingr these e for other uses and I am not confined solely fectivewidths, the output of the unit may be to gear pumps. varied to anyextent desired from minimum The following specification, of which the tomaximum at any given speed. It is in this drawings form a part,describes my invention 39 manner that I secure a variable volume of inthis preferred form. 80

delivery with constant speed and further- In the drawings:

more, may automatically maintain that vol- Fig. 1 is a side elevation ofthe discharge ume at any given amount by a valve arrangeside of thepump.

nient which utilizes the pressures within the Fig. 2 is an isometric ofa stripped pump 35 unit to control the extent to which the faces showingthe gears, spiders and follower plate.

of the revolving members are exposed for Fig. 3 is an elevation of thedrive end of a any given setting of the valve. pump arranged fornon-lubricating fluids.

Such units, as illustrated by pumps or Fig. 4 is a longitudinal sectionof a pump blowers` are widely adaptable to industrial at full volumesetting. J uses where variable volume or rate of delivery Fig. 5 is asection through 5 5 of Fig. 4. 90

is desired such as for hydraulic presses, con- Fig. (i is a sectionthrough 6 6 of Fig. 4. trol of' volume in different stages of oil refin-Fig. 7 is a longitudinal section Similar to ing and in chemicalprocesses, temperature Fig 4, but at minimum volume setting. control byfluids. supply to oil burners, draft Fig. 8 shows the valve and portarrangeaild air pressures and inniiiiiei'able other uses ment. 95 whichare evident. Similarly, units embody- Fig. 9 is an isometric phantomshowing the ing my invention are especially well adapted connections andpassages to the valve chamto feed fluid motors and many advantagesacber.

crue therefrom. This form of transmission- Fig. l0 illustrates atransmission arrange- 5" variable unit and fluid motor-provdes an ment.10

The pump casing is shown at 1, supported by the base 2 and having aninlet 3 and an outlet 4. The casing is closed by the head 7 with boltsor studs 8. In the lower part of the casing is a shaft 9 (Figs. 4 and7)which lits in the casing and head as shown and is held againstmovel'nentby. a set screw (not shown) in the casing end. On the casingend of this shaft is a spider 10 having a bearing 11 and a gear 12having a bearing 13 in which is an ofl'set 14 against which the gear 12abuts. This spider and gear are always in engagement (Fig. 2) and bothfit closely within the circular portion of the cas ing where theyrevolve. The inner portion of the spider is hollow to a depthapproximately equal to the width of the face of the gear 12 and is soarranged Circumferentially as to be the complement of the gear; that is,the spider conforms in shape to the tooth spaces and is of the samediameter as the gear so that, in effect, the spider acts as a movablewall or sealing means as it closes over the gear in the manner to bedescribed later.

Above the fixed shaft 9 is the power driven shaft 15 which turns in thebearings 16 of the casing and 17 of the head. Fixed to this shaft by thekey 18 is another gear 19 adapted to mesh with the gear 12. Also on thissame shaft and in engagement with the gear 19 is the spider 20 ofsimilar construction to the spider 10 and having a like relation to gear19. So far it will be seen that gear 19 will drive gear 12 and thatspiders 20 and 10 will revolve with their respective gears and that theeffective width of the gear teeth in engagement can he varied by thespiders coming over their respective gears. In order that thesemovements may be simultaneous, I provide a follower plate 21. Thisfollower fits over a reduced end of the spider 20 and is retained by thenut 22 (Fig. 4) the spider being free to rotate while the follower isstationary. Extending downward, the follower is developed into a hollowportion around the shaft 9 with its outer edge abutting against thelower gear 12 and flush with the inner face of spider 20. Gear 12 isretained against the follower plate 21 by the nut 23 on the bearing 13which rotates with gear 12 on shaft 9. It will thus be seen that anylongitudinal movement of the follower 21 will move the spider 20 overthe gear 19 and the gear 12 into the spider 10 to decrease the degree ofengagement of the working gears so that-the two spiders fitting closelywithin the casingthe effective width of the gear faces 24 (Flg. 4) isreduced and may be still further reduced to its minimum shown in Fig. 7at 24.

When lin operation` the internal pressure developed in the pump will actlongitudinally against the faces of the spiders and against the exposedarea of the follower plate and tend to force the upper spider and thefOllower plate to their extreme position toward the head 7 and thus keepthe gears in their maximum degree of mesh as in Fig. 4 and the pump atits greatest output. In order to overcome this and permit of any easilymade and stable setting of the follower plate 21 with its attachedspider 20 and gear 12 at any desired point for the particular volume ordelivery wanted, I provide a balanced valve whereby the pressures arebalanced andthe follower-spider-gear assembly will automatieally seekits position according to the setting of the valve.

Within the follower 21 (Figs. 8 and 9) is apvalve chamber 25 in whichfits a piston valve 26 having pistons 27 and 28. Toward the extremitiesof this valve chamber are two exhaust ports 29 and 30 connected by thecut 31 in the side of the follower 21. A second exhaust passage 33 leadsfrom the valve chamber across the follower 21 to an outlet 34 on theinlet or suction side of the pump. Therefore the portions of the valvechamber nutside of the pistons 27 and 28 will always be open to thesuction of the pump. From the outlet or pressure side of the pumpanother cut 35 in the side of the follower 21 leads to the port 36 inthe central portion of the valve chamber. Therefore the space betweenthe pistons 27 and 28 of the valve will always be at the output pressuredeveloped by the pump. Also leading from the valve chamber is a port 37and passage 38 leading upward to theannular groove 38 in the rear ofspider 20 which in turn connects with the passage 38b to the interior ofthis spider. Also a port 39 goes to the passage 40 and thence to thepoint 41 where it opens into the circular cut 42 in the face of thefollower 21. concentric series of holes 43 passing through the gear 12and opening into the inner portion of the spider 10 (Figs. 4, 8 and 9).Likewise, there is a passage 44 connecting the valve chamber with thelower recessed Portion of the follower plate.

The valve/26 may be connected to any suitable actuating mechanism suchas is shown This circular cut 42 registers with al in Fig. 1 where thevalve is connected to the operating arm 45 pivoted by the link 46 andhaving a guide 47 upon which the arm 45 maybe locked in any position bythe wing .nut and bolt 48.

The operation of the pump is as follows. The shaft 15 will drive thegear 19 and carry the spider 20 with it-these two always being in somedegree of engagement. Gear 19 drives gear 12 which in turn carriesspider 10 with it-these two also being always in some degree ofengagement (Fig. 2). Then with the parts in the positions of Fig. 4,

the pump will deliver maximum volume and the valve will be in theposition of Fig. 8 with passages 38, 4() and 44 closed by the pistons 27and 28. The internal pressure acting against the faces of the spidersand follower late will tend to force them apart and keep t e gears atmaximum effective width. The pressure entering through the cut 35 andport 36 will be confined between the pistons 27 and 28 and be withouteffect. The exhaust ports 29 and 30, connecting to the exhaust opening34, remain open as always.

If it is desired to change the output of the pump-to reduce the volumeor outputthe valve 26 is advanced into the valve chamber the desiredamount. In so doing, a portion of the port 44 is uncovered by thepi'ston 27. This results in pressure flowing through cut 35, ort 36,between the pistons of the valve an out port 44 to all of the spacebetween the back of the follower plate 21 and 'the head 7. Also ports 37and 39 are uncovered by piston 28 so that the space between the upperspider and gear is open to the exhaust port 30 through passage 38,

roove 38 and passage 38b and a similar space p 1n the lower gear andspider is open to the exhaust port 30 through holes 43 in gear 12,circular cut 42 in the follower and the passage 40. Therefore, thepressure exerted behind the follower plate as just described will forceit forward; the fluid between the gears and their spiders will beexhausted as just described and the upper spider 20 will move over itsgear 19 while the lower gear 12' will move a corresponding amount intoits spider 10. Thus the effective width of engagement of the gears willbe decreased and the volume, or output, of the pump is reducedaccordingly. This forward motion of the followerspider-gear assemblywill continue until ports 38 and 44 are again closed by this followingupof the valve by the aforesaid assembly or a balance of pressuresestablished at which time the follower-spider-gear assembly comes torest and the pump will continue to deliver the reduced volume. If theforward movement of the valve is continued, the effective width of thegear teeth will continue to be reduced until the position of Fig. 7 isreached which is that of minimum or zero volume of the ump.

If it is desired to increase the volume delivered by the pump, the valveis drawn outwardly and functions as follows. The port 44 is uncovered sothat the fluid formerly under pressure between the follower 21 and thehead 7 is opened tothe exhaust and will flow out through the valvechamber and the passage 33 to the exhaust opening 34 (Figs. 8 and 9).The ports 37 and 39 will be uncovered so that fluid under pressure willflow through cut 35, port 36, between the pistons 27 and 28 and out ofport 37, passage 38, annular groove 38a to the inside of the spider 20.Fuid will also pass out of port 39, passage 40, circular cut 42 andthrough the holes 43 in gear 12 to the in side of spider 10. Ther-eLfore, as pressure 1s removed from behind the follower and there ispressure back of the ears in the spiders as well as against the aces ofthe spiders and follower, the follower will move toward the head 7, thegears will be drawn into a greater degree of engagement and theeffective width of the gear teeth increased to raise the pump volume.

Consequently, it will be seen that b a movement made easily and withoute ort the valve is shifted to change the volume of the pump at willwithout change of speed and that the elements of the pump will adjustthemselves to their proper positions according to the position of thepiston valve as so moved.

Theoretically, the follower will move to a position where the ports 44,37 and 39 are closed by the pistons 27 and 28 but it may be that theposition of equilibrium may be slightly to one side or the other butthis in no way affects the operation of the valve or ump inasmuch as,when equilibrium is established, the follower will retain the psition towhich it moves until the valve setting is again changed. It is alsoobvious that, instead of having the valve 26 manually operated as shown,it may equall well be arranged to adjust automatically t e position ofthe follower plate-and hence the output of the pump-in accordance withconditions of flow, pressure, temperature, etc.

The foregoing description contemplates the use of a fluid havinglubricating qualities or where the faces of the rotors can be lubricatedbut where other fluids are used, the wear on the rotors would beundesirable and lead to excessive leakage. In such event, I extend theshafts 9 and 15 and mount upon them a pair of gears 49 and 50 (Fig. 3)preferably of finer pitch than the pumping gears or of any desirablepitch where rotors other than gears are used. The driving is then doneby these gears and while the pumping rotors will mesh as before, therewill be no driving as between them and consequently no wear.

In Fig. I show in diagram form a transmission to which my invention iswell adapted. This pump is shown at 51 and its valve control at 52. TheHuid passes through pipe 53 to motor 54, is exhausted through pipes 58and 59 to tank 60 where it is again taken up by the pump through pipe61. The motor 54 is shown as being of .the gear type for low speedswhere the gear 55 is smaller than the gear 56 on the driving shaft 57.Such a transmission with a pump embodying the principle of my inventionprovides a range of all motor speeds between minimum and maximum withoutchange in the speed of the pump. Also this form of transmission isinvaluable for all forms of transportation, speed changers, industrialand marine uses, etc., and may be combined in a very small space, issimple, ef-

iicient and rugged. No packing or other sealing means are necessary andrunnin the ump at relatively high periphera spee the fluid leakage pastthe rotors will be a ver small percentage of the pump volume anpractically constant.

It will be understood that the preferred form of m invention just setforth in the foregoing t escription of a pump and a transmission isillustrative and that many changes and adaptations in design andcombination may be lnade without departing from the spirit thereof, oraffecting the principle and I include all such within the scope of myclaims.

I claim:

1. A rotary pum tors, one being fixe and the other bein another shaft,axial? having a pair of roupon a rotatable shaft axiall movable uponmova le means adapted to move over an closel fit around said fixedrotor, other similar but axially fixed means Iadapted to receive andclosely fit around said movable rotor and a connection between theaxially movable means and gear.

2. A rotary pump having a fixed rotor and a slidable spider, a fixedspider and a slidable rotor and a follower plate connecting the slidablegear and spider.

3. In a rotary pump having rotors in engagement, a shaft on which isfixed a rotor and a slidable spider, another shaft on which is aslidable rotor and a fixed spider and a follower plate connecting theslidable spider and the slidable rotor.

4. A rotary pump having rotors in engagement, splders coacting with eachof the rotors and a follower plate associated therewith, means todistribute the internal pump pressures to selected points with relationto said rotors, spiders and follower plate and a valve device arrangedto control said distribution of pressures.

5. A rotary pump having rotors, means coacting with each rotor to varythe volume of the pump independently of its speed, an element connectingone of said means and one of said rotors and a valve device adapted tomaintain said volume varying means in any selected position.

6. In a rotary pump, a fixed gear and a slidable spider on a shaft, aslidable gear in engagement with the fixed gear and a fixed spider onanother shaft, a follower plate connecting the slidable spider and theslidable gear and a valve device in said follower plate in associationwith passages to selected points within the pump.

7. A rotary pump havin a casing containing a fixed rotor and a sli ablespider on one shaft, a slidable rotor and a fixed spider on a secondshaft, a follower plate connecting the slidable rotor and spider and apair of meshed gears mounted on said shafts exterior to said casini 8.rotary pump havin one shaft carrying a slidable spider and a xed gear, asecond shaft carrying a fixed spider and a slidable gear in engagementwith the fixed gear, a follower late connecting the slidable s ider andslidab e gear and a valve device within said follower plate adapted tomaintain the connected slidable gear slidable spider and follower platein any selected position.

9. A rotary pump having a shaft carryin a slidable s ider and a fixedgear, a secon shaft carrymg a fixed spider and a slidable gear inengagement with the fixed gear, a follower plate connecting the slidablespider and slidable gear; a valve device within said follower plateadapted to maintain the connected slidable gear, slidable s ider andfollower plate in any selected position and means exterior to the pumpto actuate said valve dev1ce.

10. A rotary pum havin a casing containing a fixed rotor an a slidalespider, a fixed spider and a slidable rotor, a follower late connectingthe slidable gear and slidab e rotor and a valve Iwithin said followerplate adapted to distribute the pressure within the casing to selectedpoints with respect to said rotors, spiders and follower plate.

11. A rotary pump having rotors in engagement and means coacting witheach rotor to vary the volume of the pump independently of its speed;said means bein actuated by the pressures generated within t e pump.

12. A constant speed, variable volume pum) having rotors in engagementand means acte upon by the ressures generated within the pump to vary te degree of engagement of said rotors; said means forming a movable wallto seal the tops and ends of the rotors and forming a closed chamber tothe extent of the meshing width of the gears.

13. A rotary pump having rotors in engagement and means co-actin witheach rotor to vary the effective portlons of said rotors.

14. A rotary pump having rotors in engagement, means co-acting with eachrotor to vary the effective portions of these rotors and a valve devicecontrollin said means.

15. A constant spee variable volume pump having rotors in engagement andmeans to vary the volume of the pump independently of its speed; saidmeans coacting with each of the rotors to form the walls of a chamberextending the meshing width of the gears.

16. A constant speed, variable volume pump having rotors in engagement,means to vary the volume of the pump independently of its speed and avalve device contained in the means; said means coacting with each ofthe rotors to form the walls of a chamber extending the meshing width ofthe gears.

17. A variable volume, constant speed pump havinglrotors in engagementand means coacting wit each rotor to vary the meshin width of the gearsin response to pressure di ferentials created within the pump.

18. A variable volume, constant speed pump having meshed rotors in achamber and means coacting with each rotor to form a movable wall ofsaid chamber.

19. A variable volume, constant speed pump having meshed rotors in achamber,

means coacting with each rotor to form a movable wall of said chamberand a valve device contained in said means.

In testimony whereof I have signed my name to this specification this26th day of March, 1927.

REGINALD J. S. PIGOTT.

